About
"CAM-Cancer" is the name of a project entitled "Concerted Action for Complementary and Alternative Medicine Assessment in the Cancer Field" (CAM-Cancer). Originally funded by the European Commission (EC) within the Framework 5 Programme, it is now hosted by the National Information Center for Complementary and Alternative Medicine (NIFAB) at the University of Tromsø, Norway.

Abstract and key points

Few cases of adverse effects have been reported but there are serious safety concerns for thujone-containing extracts

Artemisia absinthium, also known as wormwood, is a plant from the Asteraceae/Compositae family which has been used medicinally since Roman times. It has been used orally and topically and small quantities are found in some foods and alcoholic drinks. Traditional use is based on wormwood as a bitter tonic for digestive disorders and loss of appetite. Wormwood has been claimed to have anti-cancer effects but there is no evidence from clinical trials with cancer patients to support this claim. Few cases of adverse effects have been reported but there are safety concerns for extracts that contain thujone which is reported to cause a wide range of toxic effects.

What is it?

Description

Artemisia absinthium (Absinth(e), Wormwood, Common wormwood), Family: Asteriaceae or Compositae) is a perennial plant, which grows as a small bush with feathery leaves and pale yellow flowers. The applicable parts are those that are above ground.1

Ingredients/Components

Wormwoodâ€™s aerial parts contain bitter principles (absinthin and anabsinthin), resins and organic acids. A volatile oil is present the composition of which has been found to vary with the largest part formed by monoterpenes. In some cases the oil contains between 10% and 90% of thujone (a monoterpene ketone) which has been linked to adverse and toxic effects.2,3 High concentrations of other monoterpenes including myrcene, and trans-sabinyl acetate have also been identified.

Application and dosage

There is no documented safe or effective dose for the use in treatment of cancer. Traditionally, wormwood has been used orally and topically. Based on traditional use, in temporary loss of appetite and mild dyspeptic/gastrointestinal disorders, a tea or tincture has been used containing the equivalent of 2-3g of the herb divided into 2 or 3 doses orally for not more than 2 weeks.4 Typical doses for other therapeutic uses are not available but the European Medicines Agency has advised that, due to potential for neurotoxicity, chemotypes with low content of thujone are preferred and the intake of thujone should not exceed 3 mg/day.4 Wormwood above ground parts have been used in flavouring alcoholic drinks but use was banned in many countries due to toxicity related to thujone. Thujone-free extracts have been used in very low concentrations in flavouring foods.1

History/providers

The plant is native to Europe, Northern Africa and Western Asia but is now found in parts of the USA and South America, although the main commercial source is Eastern Europe.2 The medical use of the wormwood plant dates back to at least Roman times and it was used as an anthelmintic (for removal of intestinal worms) and purgative, gradually becoming a general remedy for various diseases.2 Use as a â€˜cure-allâ€™ continued through to the 19th century. The adoption of wormwood-flavoured alcoholic extracts and distillates as aperitifs as well as patent medicine led to large scale production and mass use. Chronic use was linked with a syndrome known as absinthism consisting of addiction, hyperexcitability, epileptic fits and hallucination (although this has since been disputed) and this led to a decline in use.2 Interest in the plant has recently been renewed due to research in conditions such as Crohnâ€™s disease5 and stroke6.

Alleged indications

Traditional use is based on wormwood as a bitter tonic for digestive disorders and loss of appetite.4 It is promoted as a sedative and anti-inflammatory and for external use for wounds, ulcers, skin blotches and insect bites.

Mechanisms of action

Wormwood has bactericidal, insecticidal and vermicidal activity mainly due to the thujone oils.7,8 The thujone constituent is also a central nervous system stimulant which acts by modulating gamma-aminobutyric acid (GABA) type A receptors. However, this effect is more closely linked with observed toxic effects of wormwood.2 Wormwood has been reported to reduce levels of tumour necrosis factor Î± (TNF-Î±), and may have a beneficial effect in a range of conditions influenced by pro-inflammatory cytokines such this.9,10 Crude extracts of the above ground parts of the plant have been reported to have induced anti-proliferative effects on human breast cancer cells which could possibly trigger apoptosis (programmed cell death).11 In vitro studies in breast cancer and leukaemia cell lines indicate anti-proliferative activity together with promotion of apoptosis (programmed cell death).11,12 A pilot study in leukaemia cell lines found that various plants from the Asteraceae family induced cell death by apoptosis but the correlation between polyphenol content and activity was inconsistent.12

Prevalence of use

No data are available on the prevalence of use in cancer patients.

Legal issues

Wormwood is classified as an unsafe drug and banned in many countries including the USA although "thujone-free" wormwood extract has been approved by the US Food and Drug Administration (FDA) for use in foods and as a flavouring in alcoholic drinks.13 In Europe, Artemisia absinthium L. has been recognised by the European Medicines Agency as a herb for which use is based on traditional use.4

Costs and expenditures

Wormwood products are available on the internet, most commonly in the form of tincture (1:3 Alcohol Volume 45%). Based on the suggested doses, the cost of one monthâ€™s treatment would be between 7 and 36 Euros.

Does it work?

Clinical trials, case studies

No clinical trials or case studies of wormwood in humans with cancer have been published.

Is it safe?

Adverse events

Wormwood oil has been reported to cause nausea, vomiting and muscle aches.1 There have been very few anecdotal reports of the toxicity of Artemisia.2 Chronic ingestion of absinthe, an alcoholic drink containing wormwood, has been reported to be linked to a syndrome known as absinthism. This is said to consist of gastro-intestinal symptoms, insomnia and hallucinations.1 More severe adverse effects such as addiction, paralysis, epilepsy, brain damage, and psychiatric disorders and suicide have also been reported. However, the possible contribution of chronic alcohol intake has been also highlighted and the existence of a separate syndrome questioned.14 There has also been a suggestion that some symptoms may be due to adulteration with metals or toxic plants.1 One case of rhabdomyolysis leading to acute renal failure has been reported following accidental ingestion of 10ml of wormwood oil purchased on the internet.15 Artemisia absinthia is a member of the Asteraceae/Compositae (daisy, sunflower etc.) family and may cause allergic reactions in people who are allergic to other plants in this group.4

Contraindications

Wormwood has been assessed as likely unsafe for use in pregnancy if amounts larger than those found in food stuffs are ingested.1 Insufficient information is available to assess its safety in lactation. Thujone containing extracts have potentially toxic effects and therefore pose a particular risk with equivocal evidence on carcinogenicity from animal studies.16

Wormwood is contraindicated in obstruction of the bile duct, cholangitis and liver disease.4

Interactions

Thujone is metabolised via the cytochrome P450 enzyme system with involvement of the specific enzymes CYP2A6, CYP3A4 and CYP2B6.16 Therefore, there is a theoretical risk of interactions with drugs and other herbs metabolised via this system. There is also a risk if used with other thujone-containing herbs such as Salvia spp. (sage) or Thuja spp.

Due to its potential effects on the central nervous system, there is a potential for interaction with anti-convulsant (anti-epilepsy) drugs 1 and with drugs that act via GABA receptors.4

One case has been reported of a probable interaction between warfarin and Artemisia absinthium leading to gastrointestinal bleeding.18

Warnings

These relate particularly to thujone-containing extracts. The European Medicines Agency recommends caution in people with gall-bladder disease or other biliary disorders and that driving and operating machinery is avoided during treatment.4 Most forms of tinctures contain alcohol.

Legal notice
The present documentation has been compiled by the CAM-CANCER Project with all due care and expert knowledge. However, the CAM-CANCER Project provides no assurance, guarantee or promise with regard to the correctness, accuracy, up-to-date status or completeness of the information it contains. This information is designed for health professionals. Readers are strongly advised to discuss the information with their physician. Accordingly, the CAM-CANCER Project shall not be liable for damage or loss caused because anyone relies on the information.